Thursday, May 19, 2011

The measurements of stratospheric temperature trends do indicate cooling which is consistent with the theory of AGW.

However, note the 'step-function' character around the eruptions of El Chichon (1982) and Pinatubo ( 1990 ). These eruptions injected particulate into the stratosphere, accounting for the temperature spikes. But when the dust settled, stratospheric temperatures fell to levels lower than before the eruption:

In fact, for the decade prior to El Chichon, there was a stratospheric warming trend. For the period after the resolution of El Chichon but before the eruption of Pinatubo, there was again a warming trend. And since the resolution of Pinatubo (sixteen years), the lower stratospheric trend has been flat. The middle and upper stratosphere have continued to cool ( again as predicted by AGW theory ), but clearly some of the cooling trend is accounted for by constituent changes forced by the volcanoes. And those changes remain poorly understood:

Blog Archive

Modeled versus Measured Temperatures for the MSU era

The upper left panel is from the NASA GISS model E output of temperatures from 1979 through 2006.The trends include known forcings to 2003 and follow the A1B scenario forcings after 2003.

The upper right panel depicts observed temperatures since 1979 from the UAH MSU.The lower right panel depicts observed temperature change from the RSS MSU record since 1979.The lower left panel depicts temperature change in the radiosonce data (RATPAC) since 1979.

The observations corroborate the model in terms of the stratospheric cooling ( blue at the top of each panel ) and in terms of the Arctic warming ( red in the lower right of each panel ).The most prominent feature of the model is the tropical upper troposphere warming ( the big red spot in the middle which is projected by many other models ).This feature is absent from the observed records.